Microwave integrated circuit package to eliminate alumina substrate cracking

Abstract

A MIC package housing that reduces or completely eliminates alumina substrate cracking due to thermal expansion rate differences between the housing and the alumina by using a low-expansion iron-nickel alloy, such as commercially available Carpenter 49, made to ASTM Specification A-753-78 (Alloy 2) and MIL-N-14411B (MR) (Composition 3 and 4). Such a housing places compressive stresses no glass-to-metal seals used in hermetic feedthroughs and the glass is fused and the stresses relieved by a special process of annealing. Manufacturing yields are improved and very large alumina substrates can be used and are attached by hard soldering.

What is claimed is: 
     
       1. An electronic device package, comprising: a housing of an alloy material, the housing having a cavity, said alloy being substantially 0.02% C, 0.50% Mn, 0.35% Si, 48.0% Ni, and the balance being substantially iron such that the thermal expansion rate of the alloy substantially matches that of alumina (nominal 99.6% Al 2  O 3 ), the housing being decarburized and oxidized;   at least one feedthrough comprising a terminal disposed within a borosilicate glass seal fused into the housing and annealed to relieve compressive stresses within said glass seal; and   an alumina ceramic substrate attached within said cavity of the housing.   
     
     
       2. The package of claim 1, further including: a lid to hermetically enclose said cavity.   
     
     
       3. The package of claim 2, wherein: the lid is suitable for joining and sealing to the housing by welding or soldering.   
     
     
       4. The package of claim 1, further including: an inert gas at substantially one atmosphere of pressure contained in said cavity by the lid.   
     
     
       5. The package of claim 1, wherein: the electronics package is a MIC housing.   
     
     
       6. The package of claim 1, wherein: the electronics package is a JEDEC "TO" series transistor case.   
     
     
       7. The package of claim 1, wherein: the alumina ceramic substrate has at least one through-hole used in a circuit contained thereon, whereby more highly integrated hybrids are possible without sacrificing manufacturing yields.   
     
     
       8. The package of claim 1, wherein: the housing is plated with a first layer of a material comprising substantially nickel, and the first layer is plated with a second layer of a material comprising substantially gold.   
     
     
       9. The package of claim 1, wherein: a hard solder is disposed between said alumina ceramic substrate and said housing so as to attach said alumina ceramic substrate to said housing, the hard solder is one from a group of gold-tin eutectic solder and gold-germanium eutectic solder.